Points Problems: 1. The Yazidi people of Iraq were saved from starvation upon be
ID: 1881334 • Letter: P
Question
Points Problems: 1. The Yazidi people of Iraq were saved from starvation upon being trapped by ISIS on the top of Mount Sinjar in 2014 from US, British, Iraqi and UN forces in Chinook Helicopters. The helicopters could not land and dropped the food, water and essential supplies amid gunfire at a height of 50 feet above the Yazidi people. To avoid gunfire but to still allow for safe arrival of the supplies, the helicopters, which were traveling horizontally, released pallets of supplies at 35 miles per hour relative to the ground below and were rolled out of the helicopters at 15 miles per hour relative to the helicopter but in the opposite direction of travel of the helicopter. Determine (a) the time required for these pallets to land on the ground and (b) the horizontal distance traveled by the pallets from the release of the helicopter until impact on the ground. Ignore wind and air resistance. Next determine (c) parts (a) and (c) again if the helicopter needed to move upwards in addition to the above described motion by 15.0 m/s to avoid gunfire.Explanation / Answer
Vh = 35mph ; Vr = -15mph ; Vp=? ; h = 50ft = 15.24m
Vr = Vp-Vh
Vp = Vh + Vr = 20mph = 5.55 m/s
This velocity is horizontal, hence vertical velocity is 0
Ux = 5.55 m/s ; Uy = 0
a)
To find time, apply 2nd ke to vertical motion
s = ut + 1/2 at^2
-15.24 = 0 -4.9 t^2
t = 1.764 s
b)
x = Ux t = 5.55 x 1.764 = 9.79m
c)
The only thing that changes due to vertical motion is Uy= 15m/s
s = ut+1/2 at^2
-15.24 = 15t -4.9t^2
t = 3.87 sec
d)
x = Uxt = 5.55 x 3.87 = 21.46m
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